[0001] The present invention relates to a method for preparing epichlorohydrins from allyl
chlorides and alkyl hydroperoxides.
[0002] As manufacturing techniques of epichlorohydrins, there are known the chlorohydrin
process, the chlorination process of allyl alcohol and the peroxide process.
[0003] In the chlorohydrin process, an allyl chloride and a chlorohydrin are used as a raw
material and as an oxidizing agent, respectively, and therefore the amount of chlorine
used therein is too great. In the allyl alcohol process, raw materials are expensive.
[0004] In the peroxide process, tert-butyl hydroperoxide, ethylbenzene hydroperoxide, cumene
hydroperoxide, hydrogen peroxide, a peracid, etc. are used as oxidizing agents. Exemplary
cases where homogeneous catalysts are used in this process are disclosed in Japanese
Patent Publication Nos.19609/'73 and 17649/'70. In this process, however, the recovery
of the catalyst is intricate and difficult, since it is dissolved in the reaction
product mixture. There is another technique for synthesizing epichlorohydrin in which
epoxidation of propylene or allyl chloride is carried out with the aid of an alkyl
hydroperoxide in the presence of a solid catalyst, and this synthetic technique is
described in Japanese Patent Laid-Open No. 55609/'74, Japanese Patent Publication
No. 30049/'75 and J. Catalysis,
31, P. 438 (1973). In these publications, the reaction is performed by using stable
tert-butyl hydroperoxide as the hydroperoxide with 2,6-di-tert-butyl-4-methylphenol
added as a stabilizer, so that epichlorohydrin is obtained in a selectivity of 73%
(on the basis of the hydroperoxide). However, when ethylbenzene hydroperoxide is used,
the selectivity is 55%, and in the case of using cumene hydroperoxide, the selectivity
is no more than 8%.
[0005] In Japanese Patent Laid-Open No. 7908/'77, there is disclosed epoxidation of olefins
by using a solid catalyst formed by esterifying a metal-silicon oxide with a primary
or secondary aliphatic alcohol. The selectivity to the desired epoxy compound seems
to be improved by using the catalyst, but no description is made with regard to epichlorohydrins.
The use of the catalyst is effective in the epoxidation of propylene.
[0006] Japanese Patent Publication No. 40526/'79 discloses a process in which a titanium-silica
catalyst is brought into contact with a silylating agent in the production of oxirane
compounds by the reaction of hydroperoxides with olefins. Allyl chloride is also illustrated
as a variation of the olefins used as the raw material, but no specific description
is made with the synthesis of epichlorohydrins.
[0007] The present inventors have already found that in the epoxidation of allyl chlorides
with an organohydroperoxide, the yield of epichlorohydrins (the molar amount of an
epichlorohydrin formed per mole of a hydroperoxide used) can be markedly increased
by using a catalyst having silanol groups on the same silicon dioxide carrier onto
which titanium atoms are bound. In this case, however, the yield of epichlorohydrins
is about 50 to 80% and it has been difficult to improve the yield further. (See EP-A-0
287 347)
[0008] It would be desirable to provide a catalyst in the presence of which the yield of
epichlorohydrins exceeds 80% in the aforesaid expoxidation reaction.
[0009] It would also be desirable to provide a method of preventing the catalyst from activity
reduction.
[0010] The present inventors have made intensive investigations with the aim of attaining
the above objects and found that by using a modified catalyst having titanium atoms
and silanol groups on its silicon dioxide carrier and formed by substituting various
substituents for a portion of the silanol groups, and moreover by using the catalyst
together with basic compounds of alkaline earth metals, one or both of these desirable
results may be attained. The present invention has been completed on the basis of
these findings.
[0011] The catalyst of the present invention is more specifically defined as a catalyst
having titanium atoms bound to a silicon dioxide carrier via oxygen atoms and also
having on the same carrier 1 to 6 silanol groups per square nanometer thereof, 1 to
50% of the silanol groups being replaced with hydrocarbon groups, alkoxy groups, acyl
groups, acyloxy groups, carbamoyloxy groups, amino groups or organosilyloxy groups.
[0012] Preferred embodiments of the invention will now be described with reference to the
accompanying drawing, wherein Fig. 1 is a drawing illustrating some examples of the
relation between the reaction time and epichlorohydrin yield when a modified catalyst
and an unmodified catalyst for use in the present invention are employed.
[0013] In the drawing, the abscissa represents the reaction time in a batch reaction while
the ordinate indicates the difference between the theoretical yield (= 1) of an epichlorohydrin
based on a hydroperoxide and the actual yield (= [EP]t/[EP]theo) on a logarismic scale.
- [EP]theo:
- yield of an epichlorohydrin on molar basis when a hydroperoxide is entirely consumed
for the epoxidation reaction.
- [EP]t:
- actual yield of the epichlorohydrin on molar basis after a lapse of time t in hour.
[0014] Line (a) represents the results when the modified catalyst was used, while line (b)
shows those with the unmodified catalyst.
[0015] In the present invention, epichlorohydrin generally means epichlorohydrin and a 2-alkyl-epichlorohydrin
in which a hydrogen atom at the 2-position of epichlorohydrin is replaced with an
alkyl group having 1 to 3 carbon atoms; and allyl chlorides generally mean allyl chloride
and a 2-alkylallyl chloride in which a hydrogen atom at the 2-position of allyl chloride
is replaced with an alkyl group having 1 to 3 carbon atoms. These allyl chloride and
substituted allyl chlorides are used as raw materials for the respective corresponding
epichlorohydrin and substituted epichlorohydrins.
[0016] Generally, the alkyl hydroperoxide means cumene hydroperoxide, ethylbenzene hydroperoxide,
tert-butyl hydroperoxide or cyclohexyl hydroperoxide.
[0017] The unmodified catalyst, on the basis of which the modified catalyst of the present
invention is prepared, is a catalyst which has titanium atoms bound to a silicon dioxide
carrier via oxygen atoms and also has silanol groups on the same carrier.
[0018] This catalyst is generally prepared in the following manner:
(1) A titanium halide, an alkoxytitanium, or a carbonyl compound of titanium, is brought
into contact with a silica hydrogel having a suitable surface area and a suitable
surface concentration of silanol groups, and the resulting hydrogel is heated at a
low temperature enough to leave the silanol groups thereon in an atmosphere of a non-reducing
gas or an oxygen-containing gas.
(2) After silanol groups of a carrier are partially etherified with an alcohol or
esterified with an acid, the above-mentioned titanium compound is supported on the
carrier, and then the ether groups or ester groups are removed therefrom to reproduce
the silanol groups on the surface of the carrier.
(3) After a silica carrier is dehydrated so that the surface of the carrier may have
siloxane bonds, the above-mentioned titanium compound is supported thereon, and then
the carrier is hydrated by a water vapor treatment to impart a necessary number of
silanol groups to the surface thereof.
[0019] The silica hydrogel used herein may include those prepared by precipitation from
an aqueous sodium silicate solutin by acids, by decomposition of silicates, by combustion
of ethyl silicate, or by other procedures. The silica hydrogel incorporates silanol
groups on the surface and has a specific surface area of 1 m²/g or more, preferably
100 m²/g or more, a pore diameter of 50 Å (5 nm) or more, preferably 100 Å (10 nm)
or more and a pore volume of 0.01 ml/g or more, preferably 0.1 ml/g or more, the number
of the silanol groups on the surface ranging from 1 to 6, preferably from 3 to 6 per
square nanometer (10⁻¹⁸ m²) of the surface area.
[0020] Liquid titanium compounds are preferred on account of their easy usage, and hence
titanium tetrachloride, an alkoxytitanium and the like are used. These titanium compounds
may be impregnated directly in a silica hydrogel or alternatively impregnated in a
silica hydrogel after diluting the titanium compound with a solvent such as a hydrocarbon
or an alcohol.
[0021] To cause a silica hydrogel to support a titanium compound, the former is brought
into contact with the latter in an innert gas atmosphere. Afterward, the solvent used
with the titanium compound is removed by heating the silica hydrogel under atmospheric
pressure or under reduced pressure. Subsequently, the silica hydrogel is further heated
at a comparatively low temperature, preferably at a temperature in the range of 100°
to 250°C in an atmosphere of a non-reducing gas such as nitrogen, argon or carbon
dioxide, or an oxygen-containing gas such as air, so that an unmodified catalyst can
be prepared.
[0022] The time required for the heating treatment ranges from 0.5 to 10 hours, usually
from 1 to 5 hours. The temperature and time for the heat treatment have a great influence
on the number of the silanol groups on the carrier, and therefore these conditions
are very important in the manufacture of the catalyst.
[0023] In the catalyst obtained in the above manner, titanium atoms are bound to silicon
atoms via oxygen atoms. The concentration of titanium is 0.01 to 20 titanium atoms,
preferably 0.5 to 9 titanium atoms per square nanometer of the specific surface area.
In the case of the carrier having a specific surface area of 100 m²/g, the number
of 0.5 to 9 titanium atoms per square nanometer is comparable to a titanium supporting
concentration of 0.4 to 7 wt%. The hydroperoxide is supposed to be activated when
coordinated with the titanium atoms.
[0024] However, the raw material, for example, an allyl chloride, gives the hydroperoxide
low selectivity to the desired epoxide so far as conventional catalysts are used,
since the reactivity of the double bond is low due to the strong electronegativity
of the chlorine atom.
[0025] Thus, an attempt was made to modify the silanol groups of the silanol-titanium catalyst
obtained in the manner as described above. The surface reforming of silicon oxide
powder and its surface characteristics are illustrated, for example, in Hyomen (Surface)
Vol. 11, p. 591 (1973). However, no description is made there of the effects of the
surface-reformed products on specific reactions. With the conventional reforming processes
in view, the present inventors have made attempts to partially modify the silanol
groups with various substituents, and found that modified catalysts obtained by replacing
1 to 50% of the silanol groups with hydrocarbon groups, alkoxy groups, acyl groups,
acyloxy groups, carbamoyloxy groups, amino groups or organosilyloxy groups as the
substituents have marked effects on the epoxidation of allyl chlorides with alkyl
hydroperoxides.
[0026] As an exemplary hydrocarbon group used as the substituent, there may be mentioned
a straight, branched or cyclic alkyl group which has 1 to 20 carbon atoms and may
be replaced with one or more halogen atoms or aromatic groups, or an aromatic hydrocarbon
group which has 6 to 12 carbon atoms and may be replaced with one or more halogen
atoms. These groups may be introduced into an unmodified catalyst in the following
manner: An unmodified catalyst is dried and then treated with thionyl chloride at
a temperature ranging from room temperature to 200°C to convert a portion of the surface
silanol groups to chloride. The resulting catalyst is reacted at a temperature ranging
from room temperature to 100°C with an alkyl lithium or Grignard reagent containing
the corresponding hydrocarbon group described above.
[0027] The modified catalyst so obtained is rendered hydrophobic on the surface, exhibits
strong resistance to hydrolysis between the silicon atom and modified groups, and
hence has a high activity.
[0028] Exemplary alkoxy groups (RO-) used as the substituents may include those in which
R is a straight, branched or cyclic alkyl or aralkyl group having 1 to 20 carbon atoms.
These alkoxy groups may be introduced into an unmodified catalyst by heating the catalyst
together with the corresponding alcohol or phenol, preferably at the critical temperature
of the alcohol or phenol. Where R is a methyl group, the catalyst may be methoxylated
with diazomethane. The thus-obtained alkoxy group-modified catalyst is rendered hydrophobic
on the surface. Although the resistance to hydrolysis between the silicon atom and
alkoxy groups is weaker than that in the case of the hydrocarbon group substitution,
the catalyst is more economical in view of the raw materials for the substituents
and the substitution procedures of the two cases.
[0029] Where the substituents are acyl groups, their introduction may be carried out in
the following manner: An unmodified catalyst is treated at a temperature ranging from
room temperature to 200°C with thionyl chloride to convert the silanol groups on the
surface to chlorides. The resulting catalyst is brought into contact with metallic
lithium or metallic sodium in a tetrahydrofuran solvent to form a silyl-lithium compound
or silyl-sodium compound. This compound is then reacted with an acid chloride (acyl
chloride), whereby the corresponding acyl groups can be introduced into the catalyst.
such modification with acyl groups increases the electronegativity of the silica carrier
and also enhances the electropositivity (or positive charge) of the titanium, contributing
to the activation of the catalyst.
[0030] When the substituents are acyloxy groups, they may be introduced into an unmodified
catalyst by reacting the catalyst with a ketene, acid chloride or acid anhydride under
heating. Since the by-produced hydrochloric acid or carboxylic acid causes a reduction
in the selectivity to the epoxidation reaction, it is advisable to wash the resulting
catalyst with a hexane solvent containing pyridine and thereafter dry it by heating
at a temperature ranging from 100°C to 200°C under vacuum so as to thoroughly remove
the by-produced acid. Thus, a satisfactory catalyst can be obtained. By introducing
acyloxy groups, the same characteristics as obtained in the introduction of acyl groups
can be obtained, but the electropositivity of the titanium atom is made larger.
[0031] Carbamoyloxy groups may be introduced into an unmodified catalyst by reacting the
catalyst with an alkyl isocyanate or aromatic isocyanate at a temperature ranging
from room temperature to 100°C. The introduction of carbomoyloxy groups may contribute
to making the surface of the catalyst weakly hydrophobic.
[0032] The amino group-modified catalyst may be obtained by heating a carbamoyloxy group-introduced
catalyst at 150°C or above under vacuum to cause a decarboxylation reaction and thereby
to convert it to the corresponding amino compound. Another method of introducing amino
groups is to react the unmodified catalyst, whose surface has been converted to a
chloride by reacting with thionyl chloride, with an alkyl amine, aralkyl amine or
aromatic amine having 1 to 20 carbon atoms. At this time, the reaction may be conducted
in the co-presence of a solvent such as pyridine. The introduction of amino groups
may contribute to the removal of acidic points on the surface of the catalyst.
[0033] When the substituents are organosilyloxy groups,
may be illustrated as their general formula. In the formula, R¹, R² and R³ are individually
a hydrogen atom, a halogen atom, an aromatic hydrocarbon group, an alkyl group which
has 1 to 20 carbon atoms and may be replaced with one or more halogen atoms, an aryl
group which has 6 to 12 carbon atoms and may be replaced with one or more halogen
atoms, or an alkoxy, aralkyloxy or aryloxy group having 1 to 20 carbon atoms. These
groups may be introduced into an unmodified catalyst by heating the catalyst with
an alkyl chlorosilane, alkoxychlorosilane, dialkylsilazane or dialkoxysilazane. The
modified catalyst so obtained is rendered hydrophobic on the surface, exhibits strong
resistance to hydrolysis between the silicon atom and organosilyloxy groups, and has
a high activity.
[0034] The modification ratio of the surface silanol groups is important from the standpoint
of the nature of the catalyst. This is because the hydroperoxide is activated by adsorption
to the titanium atom while the allyl chloride is adsorbed to the silanol groups for
their activation. Therefore, when the catalyst is calcined at such high temperatures
as to reduce the number of the surface silanol groups or the surface modification
is so complete that the surface silanol groups are eliminated, the activity of the
catalyst is impaired and the reaction is obstructed substantially.
[0035] The ratio of surface modification is largely dependent on the kind of modifying groups.
A smaller ratio of modification is preferred when bulky groups are used. With less
bulky methyl groups, it is allowable to increase the modification ratio up to 50%
for those catalysts having a high concentration of silanol groups on the surface.
With any substituents, the modified catalyst whose modification ratio is less than
1% can not be expected to give a distinct effect over the corresponding unmodified
catalyst.
[0036] In order to react an alkyl hydroperoxide with an allyl chloride in the presence of
at least one of the catalysts of the present invention, the raw materials may be diluted
with a solvent prior to the reaction. Suitable solvents may include ethyl benzene
and cumene which are reaction raw materials for the production of the corresponding
hydroperoxides, chlorine-based alkylated compounds, and methylphenylcarbinol, cyclohexanol
and tert-butanol which are formed from the corresponding hydroperoxides. No particular
limitation is imposed on the concentration of the hydroperoxide. However, any solvent
having 5 to 90 wt% of hydroperoxide is commonly employed.
[0037] In the proportion of an allyl chloride to a hydroperoxide, it is desirable to use
the allyl chloride in excess of the hydroperoxide. In general, the yield may be improved
by using 2 moles or more, preferably 5 moles or more of an allyl chloride per mole
of a hydroperoxide. However, an excessively high molar ratio of an allyl chloride
causes the yield to reach a limit. Hence, a molar ratio of less than 50 is appropriate
from an economical point of view.
[0038] The reaction may be either a batch reaction or a continuous reaction. The catalyst
may be used in a state of either suspension or fixed bed.
[0039] The amount of the catalyst used is 0.01 wt% or more and preferably ranges from 0.05
to 30 wt% based on the hydroperoxide. The reaction temperature is generally in the
range of 0° to 250°C, preferably in the range of 20° to 150°C. No particular restrictions
are placed on the reaction pressure. Any reaction pressures under which the reaction
system is kept liquid can be employed.
[0040] In the foregoing reaction in the presence of the catalyst of the present invention,
it is possible to prolong the life of the catalyst significantly by the co-existence
of a basic compound of an alkaline earth metal. The basic compound of an alkaline
earth metal may include oxides, hydroxides, carbonates and organic acid salts of alkaline
earth metals. The basic compound is a compound represented by the following formula
MO, M(OH)₂, M(OH)X, MCO₃ or MX₂ wherein M represents an alkaline earth metal atom
such as Be, Mg, Ca, Sr and Ba and X indicates a halogen atom such as Cl, Br and I
or a monovalent organic acid group. The compound may contain its water of crystallization.
[0041] These basic compounds may be used singly or as a mixture of the two or more, or as
a complex composition. They may also be supported on the modified catalyst of the
present invention. Further, they may be used in the form of being supported on other
carriers.
[0042] The amount of the basic compound used is 0.01 to 10 times by weight that of the modified
catalyst used, and preferably is 0.1 to 3 times by weight because the effect lasts
as long as the basic characteristics remain.
Examples:
[0043] The present invention will be illustrated specifically by reference to the following
examples.
Preparation of an unmodified catalyst (A):
[0044] At 25°C, 2,170 g of a 30 wt% aqueous sodium silicate solution was mixed with 27 wt%
sulfuric acid, and reaction was then performed at a pH of 1.5 for 1.5 hours to obtain
a silica sol, and the latter was allowed to stand for 1.5 hours, so that its gelation
took place. The thus-obtained gel was washed with ammonia water having a pH of 10.5
at 80°C and was successively washed with water repeatedly, until the Na content had
reached a level of 0.05 wt% or less. Then, this gel was dried at 150°C overnight to
prepare a silica hydrogel.
[0045] This silica hydrogel had a surface area of 300 m²/g and an average pore diameter
of 140 Å, and according to its thermogravimetric analysis, the number of silanol groups
on the surface thereof was 6.0 per square nanometer (2.7 mmols/g).
[0046] Sixty grams of this silica hydrogel was added to a mixed solution of 120 ml of ethanol
and 2.38 g of titanium tetrachloride, and the mixture was then agitated for 30 minutes
so that the silica hydrogel was impregnated with the titanium tetrachloride. The ethanol
was distilled off from the gel under atmospheric pressure. The resulting gel was dried
at 100°C under a reduced pressure of 3 Torr for 1 hour and then heated at 200°C for
2 hours in a stream of air to obtain an unmodified catalyst (A).
[0047] On the thus-obtained carrier, 0.42 titanium atom per square nanometer of its surface
was supported (0.21 mmol/g). The number of the silanol groups on the surface was 4.7
per square nanometer.
Example 1:
[0048] Twenty grams of the unmodified catalyst (A) obtained as described above was fed in
a glass-made 4-neck flask with an inner volume of 200 ml. The contents were heated
up to 75°C under moderate agitation, added dropwise with 2.4 g of thionyl chloride,
and aged for 2 hours under heating. The gas thereby evolved was absorbed in an aqueous
sodium hydroxide solution by way of a condenser. After completion of the reaction,
the contents were raised up to 150°C and heated for 2 hours in a stream of nitrogen
to remove unreacted raw materials and substitute chlorine atoms for the silanol groups.
Thus, a silica gel having its surface chlorinated was obtained. Its elementary analysis
revealed that the substitution ratio by chlorine atoms was 32% of the silanol groups.
[0049] The silica gel having its surface chlorinated was added to 50 g of diisopropyl ether
containing 0.66 g of methyl lithium and the mixture was agitated for 3 hours to effect
methylation of the gel. Upon completion of the reaction, the silica gel which had
been separated by filtration was washed with 50 g of ethyl ether and dried. This dried
product was heated at 200°C for 2 hours to prepare a methyl group-modified catalyst.
Its elementary analysis clarified that the substitution ratio by methyl groups was
24% of the silanol groups.
[0050] In an stainless steel autoclave with an inner volume of 300 ml were added 12.0 g
of the methyl group-modified catalyst obtained in the foregoing preparation, 128.5
g of allyl chloride and 30.5 g of a cumene solution containing 40 wt% of cumene hydroperoxide
to cause reaction at 40°C for 10 hours. The concentration of the residual hydroperoxide
in the reaction solution was determined by iodometry so that the conversion of the
cumene hydroperoxide was calculated. The epichlorohydrin yield was determined from
the analysis of the reaction solution by gas chromatography. The relation between
the reaction time and epichlorohydrin yield is illustrated as line (a) in Fig. 1.
As seen in Fig. 1, the yield of epichlorohydrins is observed to increase with the
passage of reaction time.
Comparative Example 1:
[0051] Reaction was carried out in the same manner as in Example 1 except for the use of
the unmodified catalyst (A) in place of the methyl group-modified catalyst. The relation
between the reaction time and epichlorohydrin yield is shown as line (b) in Fig. 1.
With the unmodified catalsyt, it is observed that the increase of epichlorohydrin
yield suddenly reaches the top as the reaction time elapses.
Example 2:
[0052] Seventy grams of carbitol, 42.0 g of a 40 wt% aqueous potassium hydroxide solution
and 20 ml of ethyl ether were charged in a 1000 ml flask, followed by dropwise addition
under agitation of a solution formed by dissolving 43.0 g of p-tolylsulfonyl methylnitrosoamide
in 280 ml of ethyl ether. The diazomethane evolved was passed through a flask in which
10.0 g of a previously-prepared unmodified catalyst (A) was suspended in 200 ml of
ethyl ether to effect methoxylation of the catalyst. Following the reaction, the catalyst
was heated at 200°C for 2 hours in a stream of nitrogen to obtain a methoxylated modified
catalyst. As a result of its elementary analysis, the substitution ratio by methoxy
groups was 17% of the silanol groups.
[0053] To 12.0 g of the above methoxy group-modified catalyst were added 66 g of allyl chloride
and 48.0 g of an ethylbenzene solution containing 25 wt% of ethylbenzene hydroperoxide.
The resulting mixture was subjected to reaction at 90°C for 2 hours. The results are
given in Table 1.
Comparative Example 2:
[0054] Reaction was carried out in the same manner as in Example 2 except for the use of
the unmodified catalyst (A) in place of the methoxy group-modified catalyst. The results
are given in Table 1.
Table 1
Time-dependent variation of epichlorohydrin yield (%) |
Reaction time (hr) |
0.5 |
1.0 |
1.5 |
2.0 |
Example 2 |
50 |
73 |
82 |
88 |
Comp. Example 2 |
65 |
73 |
76 |
77 |
Example 3:
[0055] The interior of a 500 ml autoclave containing 30.0 g of the unmodified catalyst (A)
was evacuated, in which 100 ml of anhydrous ethanol was successively sucked. Under
moderate agitation, the contents were raised up to 240°C over 1.5 hours. At this moment,
the pressure rised to 65 kg/cm²G. The valve was immediately opened to discharge the
ethanol outside so that the pressure was releated to atmospheric, and then the valve
was closed. The autoclave and immersed in a water bath and sucked for 4 hours under
vacuum to remove the residual ethanol. Then, the catalyst so obtained was taken out
of the autoclave, packed in a quartz tube, and heated at 200°C for 2 hours in a stream
of nitrogen to obtain an ethoxylated modified catalyst. As a result of its elementary
analysis, the substitution ratio by ethoxy groups was 38% of the silanol groups.
[0056] To 7.5 g of the ethoxy group-modified catalyst were added 77.0 g of allyl chloride
and 12.0 g of a toluene solution containing 75 wt% of tert-butyl hydroperoxide, and
the mixture was subjected to reaction at 40°C for 10 hours. The results are given
in Table 2.
Comparative Example 3:
[0057] Reaction was carried out in the same manner as in Example 3 except for the use of
the unmodified catalyst (A) in place of the ethoxy group-modified catalyst. The results
are given in Table 2.
Table 2
Time-dependent variation of epichlorohydin yield (%) |
Reaction time (hr) |
1.0 |
2.0 |
5.0 |
10.0 |
Example 3 |
40 |
57 |
74 |
88 |
Comp. Example 3 |
65 |
75 |
78 |
79 |
Example 4:
[0058] A glass-made 4-neck flask with an inner volume of 300 ml, provided with an agitator,
dropping funnel and gas inlet nozzle, was fully replaced with nitrogen. In the flask,
100 ml of tetrahydrofuran dehydrated by Molecular Sieve 5A and 0.4 g of metallic lithium
were fed successively. Under agitation at room temeprature, 20 g of a chlorinated
catalyst, which had been obtained by treating the silanol groups on the surface of
the unmodified catalyst (A) with thionyl chloride in the same manner as in Example
1, was added and the mixture was subjected to reaction for 6 hours at room temperature.
The reaction liquid was added dropwise with 4.8 g catalyst chloride, followed by reaction
at 65°C for 3 hours under heating. Then, the catalyst obtained by filtration was washed
twice with 100 ml of tetrahydrofuran, dried overnight under reduced pressure, and
heated at 200°C for 2 hours in a stream of nitrogen. As a result of the elementary
analysis of the modified catalyst obtained, the substitution ratio by acetyl groups
was 16% of the silanol groups.
[0059] In a stainless steel autoclave with an inner volume fo 200 ml, 10.0 g of the acetyl
group-modified catalyst obtained in the foregoing preparation, 50.0 g of allyl chloride
and 40.0 g of an ethylbenzene solution containing 25 wt% of ethylbenzene hydroperoxide
were added, and the mixture was subjected to reaction at 80°C for 2 hours. The results
are given in Tale 3.
Comparative Example 4:
[0060] Reaction was carried out in the same manner as in Example 4 except for the use of
the unmodified catalyst (A) in place of the acetyl group-modified catalyst. The results
are given in Table 3.
Table 3
Time-dependent variation of epichlorohydrin yield (%) |
Reaction time (hr) |
0.5 |
1.0 |
1.5 |
2.0 |
Example 4 |
43 |
64 |
77 |
82 |
Comp. Example 4 |
51 |
67 |
72 |
73 |
Preparation of an unmodified catalyst (B):
[0061] At 25°C, 2,170 g of a 30 wt% aqueous sodium silicate solution was mixed with 27 wt%
sulfuric acid, and reaction was then performed at a pH of 1.5 for 1.5 hours to obtain
a silica sol, and the latter was allowed to stand for 1.5 hours, so that its gelation
took place. The thus-obtained gel was washed with ammonia water having a pH of 10.5
at 80°C and was successively washed with water repeatedly, until the Na content had
reached a level of 0.05 wt% or less. Then, this gel was dried at 150°C overnight to
prepare a silica hydrogel. This silica hydrogel had a surface area of 300 m²/g and
an average pore diameter of 140 Å, and according to its thermogravimetric analysis,
the number of the silanol groups on the surface was 6.0 per square nanometer (2.7
mmols/g).
[0062] In a 300 ml glass-made 4-neck flask were fed 100 g of the above silica hydrogel (20
- 40 mesh) and 200 ml of anhdyrous ethanol (water content: 30 ppm). To the resulting
mixture was added 9.5 g of ethyl orthotitanate under agitation so that the hydrogel
was caused to support titanium at room temperature for 1 hour. After removing the
ethanol by distillation at atmospheric pressure, the hydrogel was dried at 110°C for
5 hours under reduced pressure and then heated at 200°C for 2 hours in a stream of
air to obtain an unmodified catalyst (B). The elementary analysis of the catalyst
revealed that it carried 0.84 titanium atom per square nanometer of its surface (0.42
mmol/g). Its thermogravimetry clarified that the number of the silanol groups on the
surface was 4 per square nanometer (1.8 mmols/g).
Example 5:
[0063] A quartz-made reaction tube (inner diameter: 15 mm, length: 300 mm), provided with
a preheater precedingly, was heated to 600°C in an electric furnace. While passing
therethrough gaseous nitrogen at a rate of 40 ml/min, diketene was fed dropwise in
the preheater at a rate of 0.1 ml/min. At the outlet of the quartz reaction tube was
provided a trap cooled at -20°C, which collected unreacted diketene. A gaseous mixture
of the ketene evolved and nitrogen was introduced in a 300 ml glass-made 4-neck flask,
which had contained 50 g of the unmodified catalyst (B) and had been heated to 130°C,
under moderate agitation over 2 hours. As a result of elementary analysis, the substitution
ratio by acetoxyl groups was 29% of the silanol groups.
[0064] In a stainless steel autoclave with an inner volume of 200 ml, 10.0 g of the acetoxyl-group
modified catalyst obtained in the foregoing preparation, 50.0 g of allyl chloride
and 40.0 g of an ethylbenzene solution containing 25 wt% of ethylbenzene hydroperoxide
were fed and the resulting mixture was subjected to reaction at 80°C for 2 hours.
The results are given in Table 4.
Comparative Example 5:
[0065] Reaction was carried out in the same manner as in Example 5 except for the use of
the unmodified catalyst (B) in place of the acetoxyl group-modified catalyst. The
results are given in Table 4.
Table 4
Time-dependent variation of epichlorohydrin yield (%) |
Reaction time (hr) |
0.25 |
0.5 |
1.0 |
1.5 |
2.0 |
Example 5 |
45 |
63 |
78 |
86 |
90 |
Comp. Example 5 |
51 |
67 |
76 |
78 |
79 |
Example 6:
[0066] A solution formed by dissolving 10.1 g of phenyl isocyanate in 200 ml of benzene
was fed in a 300 ml glass-made 4-neck flask provided with an agitator, which had previously
contained 50.0 g of the unmodified catalyst (B), and the resulting mixture was heated
at 80°C for 3 hours at reflux with gentle agitation. Then, the solvent was removed
and the catalyst was washed twice with 150 ml of benzene to remove unreacted phenyl
isocyanate, followed by drying at 80°C overnight under reduced pressure. The elementary
analysis of the modified catalyst obtained revealed that the substitution ratio by
N-phenylcarbamoyloxy groups was 22% of the silanol groups.
[0067] In a 200 ml stainless steel autoclave, 10.0 g of the above modified catalyst, 76.5
g of allyl chloride and 12.0 g of a toluene solution containing 75 wt% of tert-butyl
hydroperoxide were fed and the resulting mixture was subjected to reaction at 80°C
for 2 hours under agitation. The results are given in Table 5.
Comparative Example 6:
[0068] Reaction was carried out in the same manner as in Example 6 except for the use of
the unmodified catalyst (B) in place of the N-phenylcarbamoyloxy group-modified catalyst.
The results are given in Table 5.
Table 5
Time-dependent variation of epichlorohydrin yield (%) |
Reaction time (hr) |
0.5 |
1.0 |
1.5 |
2.0 |
Example 6 |
49 |
64 |
83 |
86 |
Comp. Example 6 |
58 |
67 |
79 |
80 |
Example 7:
[0069] Twenty grams of a catalyst, obtained by substituting chlorine atoms for the silanol
groups on the surface of the unmodified catalyst (A) by using thionyl chloride in
the same manner as in Example 1 (substitution ratio: 32%), was fed in a 200 ml stainless
steel autoclave. The interior of the autoclave was evacuated and then heated to 100°C.
Under moderate agitation, 1.9 g of dimethyl amine was sucked in the autoclave and
the contents were reacted for 4 hours. After completion of the reaction, gaseous nitrogen
was passed through the autoclave while maintaining the temperature at 100°C. Then
the autoclave was evacuated so as to remove unreacted dimethyl amine. The contents
were heated at 200°C for 2 hours in a stream of nitrogen to remove hydrochloric acid.
As a result of the elementary analysis of the modified catalyst so obtained, the subsitution
ratio by amino groups was 22% of the silanol groups.
[0070] In a stainless steel autoclave with an inner volume of 200 ml were fed 10 g of the
amino group-modified catalyst obtained in the foregoing preparation, 50.0 g of allyl
chloride and 40.0 g of an ethylbenzene solution containing 25 wt% of ethylbenzene
hydroperoxide, which were then reacted at 80°C for 2 hours. The results are given
in Table 6.
Table 6
Time-dependent variation of epichlorohydrin yield (%) |
Reaction time (hr) |
0.5 |
1.0 |
1.5 |
2.0 |
Example 7 |
43 |
66 |
79 |
84 |
Comp. Example 4 |
51 |
67 |
72 |
73 |
Example 8:
[0071] In a stainless steel autoclave with an inner volume of 200 ml was fed 30.0 g of the
unmodified catalyst (B), and the autoclave was evacuated and then heated to 180°C.
Under moderate agitation, 3.0 g of hexamethyl disilazane was sucked in the autoclave
and the contents were reacted at 180°C for 4 hours. Subsequently, the ctalyst was
taken out and heated at 200°C for 2 hours in a stream of nitrogen. The elementary
analysis of the modified catalyst thus-obtained elucidated that the substitution ratio
by trimethylsilyl groups was 29% of the silanol groups.
[0072] In a stainless steel autoclave with an inner volume of 200 ml were added 12.0 g of
the silyl group-modified catalyst obtained in the foregoing preparation, 64 g of allyl
chloride and 30 g of a cumene solution containing 40 wt% of cumene hydroperoxide,
which were then reacted at 40°C for 10 hours. The results are given in Table 7.
Comparative Example 8:
[0073] Reaction was carried out in the same manner as in Example 8 except for the use of
the unmodified catalyst (B) in place of the silyl group-modified catalyst. The results
are given in Table 7.
Table 7
Time-dependent variation of epichlorohydrin yield (%) |
Reaction time (hr) |
2.0 |
4.0 |
6.0 |
10.0 |
Example 8 |
67 |
82 |
88 |
94 |
Comp. Example 8 |
73 |
77 |
78 |
80 |
Example 9:
[0074] In a stainless steel autoclave with an inner volume of 300 ml were added 12.0 g of
the methyl group-modified catalyst used in Example 1, 152.0 g of methallyl chloride
and 96.0 g of a cyclohexane solution containing 10.4 wt% of cyclohexyl hydroperoxide
and the contents were subjected to reaction at 100°C for 6 hours. The results are
given in Table 8.
Comparative Example 9:
[0075] Reaction was carried out in the same manner as in Example 9 except for the use of
the unmodified catalyst (A) in place of the methyl group-modified catalyst. The results
are given in Table 8.
Table 8
Time-dependent variation of epichlorohydrin yield (%) |
Reaction time (hr) |
1.0 |
2.0 |
4.0 |
6.0 |
Example 9 |
23 |
37 |
57 |
70 |
Comp. Example 9 |
34 |
43 |
51 |
55 |
Comparative Example 10:
[0076] Twenty grams of the unmodified catalyst (A) was fed in a glass-made 4-neck flask
with an inner volume of 200 ml and heated to 200°C under moderate agitation. To the
catalyst so heated was added dropwise 2.4 g of thionyl chloride, and the mixture was
heated over 2 hours for aging. The unreacted starting material was removed in a stream
of nitrogen so that a surface chlorinated catalyst was obtained. Its elementary analysis
clarified that the substitution ratio of the silanol groups by chlorine atoms was
75%.
[0077] This surface chlorinated catalyst was added to 100 g of isopropyl ether containing
1.5 g of methyl lithium and the resulting mixture was agitated for 5 hours, whereby
the catalyst was methylated. The methylated catalyst was heated at 200°C for 2 hours
in a stream of nitrogen to obtain a methyl group-modified catalyst with the substitution
ratio of the silanol groups of 57%.
[0078] Using this catalyst, reaction was carried out over 10 hours in the same manner as
in Example 1. The results are given in Table 9, together with the corresponding numerals
of Comparative Example 1 and Example 1.
Table 9
Time-dependent variation of epichlorohydrin yield (%) |
Reaction time (hr) |
0.5 |
1.0 |
2.0 |
4.0 |
10.0 |
Comp. Example 1 |
49 |
69 |
77 |
80 |
81 |
Example 1 |
26 |
54 |
71 |
84 |
95 |
Comp. Example 10 |
8 |
11 |
19 |
32 |
60 |
[0079] As seen in Table 9, an increase in the surface treatment rate causes a reduction
in the reaction yield.
Comparative Example 11:
[0080] In the preparation of the unmodified catalyst (A) in Example 1, following the impregnation
of titanium, ethanol was removed by distillation, and the silica gel was dried at
100°C and then heated at 800°C for 2 hours in a stream of nitrogen. The catalyst thus-obtained
supported 0.42 titanium atom per square nanometer of its carrier surface. The number
of the silanol groups on the surface was 0.3 per square nanometer by the thermogravimetry.
[0081] This high-temperature calcined catalyst was ethoxylated at its surface in the same
manner as in Example 3. As a result of its elementary analysis, the substitution ratio
by ethoxy groups was 67% of the silanol groups.
[0082] To 7.5 g of the catalyst were added 77.0 g of allyl chloride and 12.0 g of a toluene
solution containing 75 wt% of tert-butyl hydroperoxide, and the mixture was subjected
to reaction at 40°C for 10 hours. The results are given in Table 10.
Table 10
Time-dependent variation of epichlorohydrin yield (%) |
Reaction time (hr) |
1.0 |
2.0 |
5.0 |
10.0 |
Comp. Example 11 |
10 |
14 |
21 |
30 |
Example 10:
[0083] In a stainless steel-made, outer-jacketed pressure-tight reactor with an inner diameter
of 20 mm and a length of 300 mm (this reactor was used likewise hereunder) were packed
10 g of the methyl group-modified catalyst (20 mesh) obtained in Example 1 and 10
g of calcium oxide (size: 60 mesh, a 500°C calcined product) in a uniformly dispersed
state. A cumene solution containing 40 wt% of cumene hydroperoxide and allyl chloride
(hereinafter referred to as ALC), at a weight ratio of the hydroperoxide to the ALC
of 1 to 10.7, were charged into the reactor separately by pumps at a liquid hourly
space velocity (hereinafter abbreviated as LHSV) of 0.3/hr per unit volume of the
modified catalyst in terms of the sum of both starting liquids. Thus, they were reacted
there at 40°C.
[0084] The concentration of the residual hydroperoxide in the reaction mixture was determined
by iodometry to calculate the conversion of the cumene hydroperoxide and the epichlorohydrin
yield was obtained from the analysis of the reaction mixture by gas chromatography.
The relation between the reaction time and hydroperoxide (hereinafter abbreviated
as HPO) conversion and the relation between the reaction time and epichlorohdyrin
(hereinafter abbreviated as ECH) yield are shown in Table 11.
Reference Example 1:
[0085] Reaction was carried out in the same manner as in Example 10 except for the use of
the reactor packed only with the methyl group-modified catalyst obtained in example
1. The results are given in Table 11.
Table 11
Reaction time (hr) |
100 |
300 |
700 |
Example 10 |
HPO conversion % |
64 |
41 |
43 |
ECH yield % |
58 |
47 |
40 |
Ref. Ex. 1 |
HPO conversion % |
53 |
40 |
30 |
ECH yield % |
48 |
37 |
27 |
Example 11:
[0086] In the reactor packed with a mixture of 10 g of the methoxy group-modified catalyst
(20 mesh) obtained in Example 2 and 10 g of barium carbonate (30 - 60 mesh), an ethylbenzene
solution containing 25 wt% of ethylbenzene hydroperoxide and ALC, at a weight ratio
of the HPO to the ALC of 1 to 10, were charged at an LHSV of 1.0/hr, and reacted there
at 90°C. The results are given in Table 12.
Reference Example 2:
[0087] Reaction was carried out in the same manner as in Example 11 except that the barium
carbonate was not used. The results are given in Table 12.
Table 21
Reaction time (hr) |
120 |
360 |
720 |
Example 11 |
HPO conversion % |
81 |
76 |
68 |
ECH yield % |
69 |
65 |
58 |
Ref. Ex. 2 |
HPO conversion % |
66 |
61 |
51 |
ECH yield % |
55 |
50 |
43 |
Example 12:
[0088] In the reactor packed with a mixture of 10 g of the ethoxy group-modified catalyst
obtained in Example 3 and 10 g of crushed calcium carbonate, a toluene solution containing
75 wt% of tert-butyl hydroperoxide and ALC, at a weight ratio of the HPO to the ALC
of 1 to 5, were charged at an LHSV of 0.3/hr, and reacted there at 40°C. The results
are given in Table 13.
Reference Example 3:
[0089] Reaction was carried out in the same manner as in Example 12 except that the crushed
calcium carbonate was not used. The results are given in Table 13.
Table 13
Reaction time (hr) |
100 |
300 |
700 |
Example 12 |
HPO conversion % |
50 |
40 |
34 |
ECH yield % |
45 |
36 |
31 |
Ref. Ex. 3 |
HPO conversion % |
41 |
31 |
26 |
ECH yield % |
37 |
28 |
23 |
Example 13:
[0090] Into 500 ml of anhydrous ethanol contained in a 1000 ml glass flask, 1 g of barium
hydroxide was added and dissolved under heating. Then, 20 g of the acetyl group-modified
catalyst obtained in Example 4 was added to the resulting solution. The solvent was
removed by distillation while mixing by means of a rotary evaporator. The resulting
solid was heated at 200°C for 2 hours in a stream of nitrogen to obtain a supported
catalyst. In the reactor was packed 10 g of the supported catalyst obtained and reaction
was conducted in the same manner as in Example 11 except for the alteration in reaction
temeprature to 80°C and in LHSV to 0.5/hr. The results are given in Table 14.
Reference Example 4:
[0091] Reaction was carried out in the same manner as in Example 13 except for the use of
the acetyl group-modified catalyst obtained in Example 4 in place of the supported
catalyst. The results are given in Table 14.
Table 14
Reaction time (hr) |
120 |
360 |
720 |
Example 13 |
HPO conversion % |
91 |
82 |
70 |
ECH yield % |
80 |
72 |
61 |
Ref. Ex. 4 |
HPO conversion % |
83 |
70 |
49 |
ECH yield % |
74 |
63 |
44 |
Example 14:
[0092] Reaction was carried out in the same manner as in Example 13 except that a mixture
of 10 g of the acetoxyl group-modified catalyst obtained in Example 5 and 10 g of
granular magnesium hydroxide was packed in the reactor. The results are given in Table
15.
Reference Example 5:
[0093] Reaction was carried out in the same manner as in Example 14 except that the granular
magnesium hydroxide was not used. The results are given in Table 15.
Table 15
Reaction time (hr) |
120 |
360 |
720 |
Example 14 |
HPO conversion % |
92 |
83 |
72 |
ECH yield 5 |
83 |
75 |
65 |
Ref. Ex. 5 |
HPO conversion % |
84 |
71 |
52 |
ECH yield % |
76 |
64 |
47 |
Example 15:
[0094] In the reactor packed with a mixture of 10.0 g of the n-phenylcarbamoyloxy group-modified
catalyst obtained in Example 6 and 5 g of granular strontium oxide, a toluene solution
containing 75 wt% of tert-butyl hydroperoxide and ALC, at a weight ratio of the HPO
to the ALC of 1 to 10, were charged at an LHSV of 0.5/hr, and reacted there at 80°C.
The results are given in Table 16.
Reference Example 6:
[0095] Reaction was carried out in the same manner as in Example 15 except that the strontium
oxide was not used. The results are given in Table 16.
Table 16
Reaction time (hr) |
100 |
200 |
400 |
Example 15 |
HPO conversion % |
88 |
85 |
72 |
ECH yield % |
75 |
72 |
62 |
Ref. Ex. 6 |
HPO conversion % |
85 |
77 |
62 |
ECH yield % |
72 |
65 |
53 |
Example 16:
[0096] In the reactor packed with a mixture of 10.0 g of the amino group-modified catalyst
obtained in Example 7 and 10 g of a crushed product of dolomite (MgCO₃·CaCO₃ composition),
an ethylbenzene solution containing 25 wt% of ethylbenzene hydroperoxide and ALC,
at a weight ratio of the HPO to the ALC of 1 to 5, were charged at an LHSV of 0.5/hr,
and reacted there at 80°C. The results are shown in Table 17.
Reference Example 7:
[0097] Reaction was carried out in the same manner as in Example 16 except that the crushed
product of dolomite (MgCO₃·CaCO₃ composition) was not used. The results are given
in Table 17.
Table 17
Reaction time (hr) |
100 |
200 |
400 |
Example 16 |
HPO conversion % |
74 |
72 |
65 |
ECH yield % |
65 |
63 |
57 |
Ref. Ex. 7 |
HPO conversion % |
75 |
63 |
42 |
ECH yield % |
68 |
67 |
37 |
Example 17:
[0098] In the reactor in which 10 g of the silyl group-modified catalyst obtained in Example
8 and 10 g of granular magnesium hydroxide had been packed, a cumene solution containing
40 wt% of cumene hydroperoxide and ALC, at a weight ratio of the HPO to the ALC of
1 to 10, were charged separately by pumps at an LHSV of 0.3 /hr, and reacted there
at 40°C. The results are given in Table 18.
Reference example 8:
[0099] REaction was carried out in the same manner as in Example 17 except that the granular
magnesium hydroxide was not used. The results are given in Table 18.
Table 18
Reaction time (hr) |
100 |
300 |
700 |
Example 17 |
HPO conversion % |
72 |
66 |
61 |
ECH yield % |
65 |
60 |
58 |
Ref. Ex. 8 |
HPO conversion % |
62 |
54 |
43 |
ECH yield % |
56 |
49 |
39 |
Example 18:
[0100] Reaction was carried out in the same manner as in Example 10 except that methallyl
chloride was used in place of the ALC and the weight ratio of the HPO to the methallyl
chloride was set at 1 to 12.6 in Example 10. The results are given in Table 19.
Reference example 9:
[0101] Reaction was carried out in the same manner as in Example 18 except that calcium
oxide was not used. The results are given in table 19.
Table 19
Reaction time (hr) |
100 |
300 |
700 |
Example 18 |
HPO conversion % |
38 |
31 |
26 |
2-methyl ECH yield % |
34 |
28 |
23 |
Ref. Ex. 9 |
HPO conversion % |
34 |
26 |
22 |
2-methyl ECH yield % |
31 |
23 |
20 |